PERFORMANCE EVALUATION OF HIGH STRENGTH CEMENT CONCRETE PAVEMENTS

Abstract

Concrete is an excellent material for road pavements. It provides a surface which is attractive, smooth-riding, strong and durable, and which requires little maintenance during its .service life. It is ideally suited to the heavy traffic of urban roads and is perhaps the only material which can withstand effectively the peculiar punishment meted out by the bullock cart to rural and farmroads. But any material, however good it is, calls for adequate and rational structural design which, too, should prove economical in the, long run. And it is this aspect which is covered in this dissertation. The design of' rigid pavements requires the consideration of traffic (Volume, weight, placement), environment, foundation support, and geometric and component analysis such as type of pavement, i.e. (CRC or jointed), transverse joint construction, type of shoulders, longitudinal joint construction etc. Ideally, a pavement design method should be able to predict the formation of all the distresses, such as blowups, corner breaks, cracking, . faulting, frozen . joints, - pumping, spelling and frost heave, as well as determination of the effect of each of these distresses on pavement performance as . measured by present serviceability, riding quality, or some other rating method that reflects the motoring public's perception of pavement serviceability.. Unfortunately, the state of the art in pavement design has not yet reached this point, although research currently under way is making significant progress in this direction. In the present study, the use of high ' strength concrete (HSC) in pavements is discussed is ' detail using various • existing design methods under different loading and support conditions and compared with that of• the experimental results obtained from the tests -performed on high strength Cement Concrete (HSC) pavement slabs. The results were also compared with that of the existing experimental work on steel fibre reinforced concrete (SFRC) pavements. It was found that the existing design methods do - not consider the number of load repetitions for the determination of the slab thickness. The IRC method of design needs to be revised and should consider the behaviour of concrete pavements under dynamic loading conditions. From the static load tests, the ultimate load carrying 'capacity of a 100tnm- 'thick HSC pavement slab at the centre, edge and corner regions were found to be 103.17 KN, 79.36 KN and 53.97 KN respectively which was in close agreement with that of the theoretical values, 97.33 KN @ centre, 59.02 KN @ edge and 50.12 KN @ corner region of the slab. But the results by IRC method are in contradiction with the above results and a slab thickness of atleast 20 mm to withstand a maximum standard axle load of 102 .KN (10.2 t legal axle load) is required. The ultimate load carrying capacity of concrete pavements increases considerably with the change in the characteristic strength of concrete and the modulus of subgrade reaction. The behaviour of HSC pavements were very much similar to that of the steel fibre reinforced concrete (SFRC) pavements and thus prove to be a better alternative for the design of future roads with high traffic intensities.